The present invention relates to improvements in apparatus for manipulating block-shaped commodities or articles in the form of paper stacks or the like. More particularly, the invention relates to improvements in apparatus for changing the direction of travel of a series of rapidly moving and closely adjacent articles, especially flat articles which are flexible, i.e., which can retain their shape only if supported along their entire undersides.
It is known to transport stacks of paper sheets or analogous flexible articles in a first plane and in a first direction by resorting to a feeding unit, to transport successive articles in a second plane and in a different second direction by resort to a removing unit, and to provide a transfer unit which delivers successive articles from the first into the second plane. Reference may be had to German Auslegeschrift No. 11 92 978 which discloses an apparatus for transport of block-shaped articles first along a first path and thereupon along a second path in a direction at right angles to the direction of transport along the first path. The articles are supplied in the form of a file or row wherein the articles are rather closely adjacent to each other, and the transfer from the first path into the second path (which is located at a level above the first path) takes place by resorting to a pusher which lifts successive articles from the first path and into the range of hook-shaped retaining members which engage one side of the lifted article to thus retain the article in the second path while the pusher returns to a level below the first path so as to be ready for the lifting of the next-following article. The articles which reach the second path are engaged by a horizontally reciprocable shifting device which removes them from the hook-shaped retaining members so that such members are then ready to engage the next-following article.
A drawback of the just described conventional apparatus is that it cannot treat all types of flat block-shaped articles, especially articles which exhibit a low resistance to deformation. Thus, whereas the conventional apparatus can readily transport bricks or similar non-deformable block-shaped articles, it cannot transport or manipulate stacks of overlapping paper sheets or like commodities which do not offer a pronounced resistance to deformation and are especially likely to undergo deformation while held by the aforementioned hook-shaped retaining members. Were a stack of paper sheets supported by such retaining members, it would exhibit a strong tendency to flex and to thereby become disengaged from the retaining members.
As a rule, flexible articles (such as stacks of paper sheets) must be supported along their entire undersides so as to prevent any or to prevent undue deformation during a change of direction of movement and/or from a path which is located at a first level into a path which is located at a different second level. Flexible articles are often manipulated by resort to a rotary conveyor in the form of a turret having radially extending compartments for discrete stacks. The turret is rotatable stepwise about an axis which is parallel to the direction of movement of the feeding unit. Successive compartments of the turret receive successive stacks from the feeding conveyor during successive intervals of dwell of the turret. At the same time, the stack which occupies the preceding compartment is removed from the turret by resorting to tongs or a similar implement. The mass of the turret is quite substantial; therefore, the turret cannot be indexed at frequent intervals, i.e., the number of articles which can be transferred per unit of time is limited by the bulk and inertia of the turret. Another drawback of such apparatus is that the articles which are ready for removal from the turret are not disposed in a horizontal plane. This presents problems in connection with further transport of articles to the next processing station or to another destination.